/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.engine.compaction.writer;

import org.apache.iotdb.db.engine.storagegroup.TsFileResource;
import org.apache.iotdb.tsfile.exception.write.PageException;
import org.apache.iotdb.tsfile.file.header.PageHeader;
import org.apache.iotdb.tsfile.file.metadata.ChunkMetadata;
import org.apache.iotdb.tsfile.file.metadata.IChunkMetadata;
import org.apache.iotdb.tsfile.read.TsFileSequenceReader;
import org.apache.iotdb.tsfile.read.common.Chunk;
import org.apache.iotdb.tsfile.read.common.block.column.Column;
import org.apache.iotdb.tsfile.read.common.block.column.TimeColumn;
import org.apache.iotdb.tsfile.write.chunk.AlignedChunkWriterImpl;
import org.apache.iotdb.tsfile.write.chunk.ChunkWriterImpl;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Map;

public class FastCrossCompactionWriter extends AbstractCrossCompactionWriter {
    // Only used for fast compaction performer
    protected Map<TsFileResource, TsFileSequenceReader> readerMap;

    public FastCrossCompactionWriter(
            List<TsFileResource> targetResources,
            List<TsFileResource> seqSourceResources,
            Map<TsFileResource, TsFileSequenceReader> readerMap)
            throws IOException {
        super(targetResources, seqSourceResources);
        this.readerMap = readerMap;
    }

    @Override
    public void write(TimeColumn timestamps, Column[] columns, int subTaskId, int batchSize)
            throws IOException {
        throw new RuntimeException("Does not support this method in FastCrossCompactionWriter");
    }

    @Override
    protected TsFileSequenceReader getFileReader(TsFileResource resource) {
        return readerMap.get(resource);
    }

    /**
     * Flush nonAligned chunk to tsfile directly. Return whether the chunk is flushed to tsfile
     * successfully or not. Return false if the unsealed chunk is too small or the end time of chunk
     * exceeds the end time of file, else return true.
     */
    @Override
    public boolean flushNonAlignedChunk(Chunk chunk, ChunkMetadata chunkMetadata, int subTaskId)
            throws IOException {
        checkTimeAndMayFlushChunkToCurrentFile(chunkMetadata.getStartTime(), subTaskId);
        int fileIndex = seqFileIndexArray[subTaskId];
        if (!checkIsChunkSatisfied(chunkMetadata, fileIndex, subTaskId)) {
            // if unsealed chunk is not large enough or chunk.endTime > file.endTime, then deserialize the
            // chunk
            return false;
        }

        flushNonAlignedChunkToFileWriter(
                targetFileWriters.get(fileIndex), chunk, chunkMetadata, subTaskId);

        isDeviceExistedInTargetFiles[fileIndex] = true;
        isEmptyFile[fileIndex] = false;
        lastTime[subTaskId] = chunkMetadata.getEndTime();
        return true;
    }

    /**
     * Flush aligned chunk to tsfile directly. Return whether the chunk is flushed to tsfile
     * successfully or not. Return false if the unsealed chunk is too small or the end time of chunk
     * exceeds the end time of file, else return true. Notice: if sub-value measurement is null, then
     * flush empty value chunk.
     */
    @Override
    public boolean flushAlignedChunk(
            Chunk timeChunk,
            IChunkMetadata timeChunkMetadata,
            List<Chunk> valueChunks,
            List<IChunkMetadata> valueChunkMetadatas,
            int subTaskId)
            throws IOException {
        checkTimeAndMayFlushChunkToCurrentFile(timeChunkMetadata.getStartTime(), subTaskId);
        int fileIndex = seqFileIndexArray[subTaskId];
        if (!checkIsChunkSatisfied(timeChunkMetadata, fileIndex, subTaskId)) {
            // if unsealed chunk is not large enough or chunk.endTime > file.endTime, then deserialize the
            // chunk
            return false;
        }

        flushAlignedChunkToFileWriter(
                targetFileWriters.get(fileIndex),
                timeChunk,
                timeChunkMetadata,
                valueChunks,
                valueChunkMetadatas,
                subTaskId);

        isDeviceExistedInTargetFiles[fileIndex] = true;
        isEmptyFile[fileIndex] = false;
        lastTime[subTaskId] = timeChunkMetadata.getEndTime();
        return true;
    }

    /**
     * Flush aligned page to tsfile directly. Return whether the page is flushed to tsfile
     * successfully or not. Return false if the unsealed page is too small or the end time of page
     * exceeds the end time of file, else return true. Notice: if sub-value measurement is null, then
     * flush empty value page.
     */
    public boolean flushAlignedPage(
            ByteBuffer compressedTimePageData,
            PageHeader timePageHeader,
            List<ByteBuffer> compressedValuePageDatas,
            List<PageHeader> valuePageHeaders,
            int subTaskId)
            throws IOException, PageException {
        checkTimeAndMayFlushChunkToCurrentFile(timePageHeader.getStartTime(), subTaskId);
        int fileIndex = seqFileIndexArray[subTaskId];
        if (!checkIsPageSatisfied(timePageHeader, fileIndex, subTaskId)) {
            // unsealed page is too small or page.endTime > file.endTime, then deserialize the page
            return false;
        }

        flushAlignedPageToChunkWriter(
                (AlignedChunkWriterImpl) chunkWriters[subTaskId],
                compressedTimePageData,
                timePageHeader,
                compressedValuePageDatas,
                valuePageHeaders,
                subTaskId);

        // check chunk size and may open a new chunk
        checkChunkSizeAndMayOpenANewChunk(
                targetFileWriters.get(fileIndex), chunkWriters[subTaskId], subTaskId, true);

        isDeviceExistedInTargetFiles[fileIndex] = true;
        isEmptyFile[fileIndex] = false;
        lastTime[subTaskId] = timePageHeader.getEndTime();
        return true;
    }

    /**
     * Flush nonAligned page to tsfile directly. Return whether the page is flushed to tsfile
     * successfully or not. Return false if the unsealed page is too small or the end time of page
     * exceeds the end time of file, else return true.
     */
    public boolean flushNonAlignedPage(
            ByteBuffer compressedPageData, PageHeader pageHeader, int subTaskId)
            throws IOException, PageException {
        checkTimeAndMayFlushChunkToCurrentFile(pageHeader.getStartTime(), subTaskId);
        int fileIndex = seqFileIndexArray[subTaskId];
        if (!checkIsPageSatisfied(pageHeader, fileIndex, subTaskId)) {
            // unsealed page is too small or page.endTime > file.endTime, then deserialize the page
            return false;
        }

        flushNonAlignedPageToChunkWriter(
                (ChunkWriterImpl) chunkWriters[subTaskId], compressedPageData, pageHeader, subTaskId);

        // check chunk size and may open a new chunk
        checkChunkSizeAndMayOpenANewChunk(
                targetFileWriters.get(fileIndex), chunkWriters[subTaskId], subTaskId, true);

        isDeviceExistedInTargetFiles[fileIndex] = true;
        isEmptyFile[fileIndex] = false;
        lastTime[subTaskId] = pageHeader.getEndTime();
        return true;
    }

    private boolean checkIsChunkSatisfied(
            IChunkMetadata chunkMetadata, int fileIndex, int subTaskId) {
        boolean isUnsealedChunkLargeEnough =
                chunkWriters[subTaskId].checkIsChunkSizeOverThreshold(
                        chunkSizeLowerBoundInCompaction, chunkPointNumLowerBoundInCompaction, true);
        if (!isUnsealedChunkLargeEnough
                || (chunkMetadata.getEndTime() > currentDeviceEndTime[fileIndex]
                && fileIndex != targetFileWriters.size() - 1)) {
            // if unsealed chunk is not large enough or chunk.endTime > file.endTime, then return false
            return false;
        }
        return true;
    }

    private boolean checkIsPageSatisfied(PageHeader pageHeader, int fileIndex, int subTaskId) {
        boolean isUnsealedPageLargeEnough =
                chunkWriters[subTaskId].checkIsUnsealedPageOverThreshold(
                        pageSizeLowerBoundInCompaction, pagePointNumLowerBoundInCompaction, true);
        if (!isUnsealedPageLargeEnough
                || (pageHeader.getEndTime() > currentDeviceEndTime[fileIndex]
                && fileIndex != targetFileWriters.size() - 1)) {
            // unsealed page is too small or page.endTime > file.endTime
            return false;
        }
        return true;
    }
}
